Railway car truck



June 17, 1941. A, W, LAlRD 2,245,864 I RAILWAY CAR TRUCK (Ittornegs June 17, 1941. I A, Wl LAlRD 2,245,864

RAILWAY GAR TRUCK Filed Aug. 30,'1940 2 Sheets-Sheet 2 Ua, llaJ lhwentor Gttornegs Patentedl'rJune 1941 s PATE;

- T' `OFFICE 2,5

RAILWAY CAR TRUCK Alton W. Laird, Watertown, N. Y., asslgnor to The'.

New York Air Brake Company), a corporation of Y I New Jersey Application August so, 1940, serial No. 354379 (c1. iss-33) 8 Claims.

lIliiis invention relates to railway brakes, particularly to brakes for high speed, light-weight passenger trains, andv serves to control the relative positions assumed by sprung and unsprung railway car truck parts as an'v incident .to application of the brakes and thus improve adhesion.

In the railway braking 'eld` there has been a departure from the former almost universal practice of operating brakes, usuallyclasp brakes, on the two trucks by a single brake cylinder on the car underframe; Y y

At present at least one brake cylinder is mounted on each truck and operates brakes thereon. Installations using two and four cylinders per truck are also in use. In the recent past these cylinders operated clasp brakes which en' gaged the wheel treads. To avoid damage to the wheels and to secure otherI related advantages,

,disc and other types of off-the-tread brakes are being increasingly used and bidfair to supplant the older type at least in those high speed railway services where the braking requirements are particularly severe.

y ficulty when off-tl'ie-wheel-tread types of'bJakes,

- supplant the'familiar clasp brake design. Herethe wheels tightlyand served to prevent' vertical vmotion, particularly upward motion, of the truck frame with respect to the wheels during the brake application.

the horizontal center line of the wheels. If unrestrained during abrake' application, the spring- 'borne truck frame will osclllate upon the equal- A izer springs during brake applications, alternate- An unexpected and heretofore bailli'ng factor in the use of disc and other oi-the-tread brakes is a seeming reduction in adhesion evidenced by an increased tendency for wheel sliding to occur. Even on trains where the reduction in body l l weight is proportionally greater than the reduction in truck weight, wheels braked with o-thetread brakes have a tendency to slide under braking ratios so low as m be well within limits heretofore considered, not merely safe, but markedly conservative.

For example, in one test on sanded rail the best adhesion with off-the-tread brakes at low speed was 1'7 per cent and at high speed'14 per cent. According to prior accepted standards from low speeds, adhesion wascommonly taken at twentyiive per cent to forty per cent on sanded rail and this was invariably adequate to prevent the silding of wheels at high speeds with retarding forces, such as those developed during the test in question. While this test probably represents an extreme case, any factor occasioning an apparent reduction of adhesion to half or less `of former value (or indeed any reduction below former values) is a serious matter. Reasonable stopping distances from high speeds must behad treads left something to be desired.

The present invention is based on theA discovery that freespring action contributes; to the diL ly increasing and-decreasing the instantaneous weight borne by the wheels. The introduction of off-the-wheel-tread types of brake .and theresulting removal of the damping eiect afforded by the brake shoes as just described permits such oscillation to occur. ljIl'ie consequent momentary reductions of the force urging the wheels to continue rotation allow them to be picked up" (i. e. locked by the brakes) during moments o f reduced loading. Once a wheel stops or nearly stops rotating, the inherent loss of adhesion completes the cycle, so that sliding becomes self-perpetuat-v ing. r v

The solution is to arrest the relative vertical motion between truck frameand unsprung parts afforded by spring action, the preferred arrangement being-to usev motor means energized simultane'ously with the brake cylinder to set the equallizing springs down solid (i. e. until their coils contact). Basically the idea is to lock the spring supvported 'truck frameto the unsprung equalizer bars in any convenient way. Setting the springs 'solid is preferred because it 'is simple and avoids Wheel truck having air operatedbrakes, willbe described by reference 'tol the accompanying drawings. v l

In the drawings` Fig. 1 is a half plan of the truck having the in.

vention applied.

Fig. 2 is a side elevation thereof. Fig. 3 is adetail elevation of one of the fo loading cylinders. A y

Figs. 4 and 5 are fragmentaryI views similar -toportions of Figs. 1 and 2 respectively vshowing a modled arrangement requiring only two small loading cylinders per truck'and using an irre- Thisfollowed from the fact that the brake shoes were invariably located below and showing a further modification in which the equalizer springs are'locked against further compression, instead of being compressed as in the embodiments of Figs. 17.

Fig. 9 is a section transverse to the the line 9--9 of Fig. 8.' l

Embodimentof Figs. 1 to 3 I The wheels are fast in pairs on axles 8 which truck onV turn in journal boxes 1. The journal boxes are confined between pedestals 8 formed integrally with the truck side frames 9. The side `frames 9 are tied together with the usual cross members, some of which appear at Ill and II. The truck frameis sustained on the boxes 1 b v equalizer springs I2 and equalizer bars I3.- Each bar I3.

rests at its ends on the boxes and is offset downward between the boxes to receive the springs I2. Each bar has cup-like seats I4 for the lower ends of a pair of springs which are of the coil compression type. The side frame has opposed cup-like seats I5 for theupper ends of the springs.

The cross members II hingedly support the upper ends of vertical links. or hangers, which carry the spring plank I6. The spring plank I6 carries elliptic springs I'I, which in turn support the bolster I8, with its center bearing I9.

The truck above illustrated is chosen as a common type to which the invention is' applicable. The details of its construction are not features of the invention, and the invention may be applied to a wide variety of trucks.

-The brakes, while of a less familiar form, are also not a feature of the invention except that they are off-the-wheel-tread brakes operated by cylinders mounted in the truck and offer no material resistance to truck-spring action. The

discs 2| are fast on axles E. and when the brakes scription.

Operating air is supplied to the brake cylinders through pipes 26, one at each side of the truck. Branches of these pipes lead to the upper or head ends of stabilizing cylinders 21, each mounted on a bracket 28. at an end of the truck frame. Each cylinder 21 has a piston -29 and rod 3I, connected by yokes 32 33 and rods 34 with the outer end of a corresponding stabilizing lever 35.

The stabilizing levers 35 are fulcrumed on brackets 36 mounted nn top of the side frames 9. The inner ends of levers 35 are pinned at 3'! to the upper ends of links 38. which extend through slots in the side frames 9 and equalizer bars I3, at the seats I5 and I4, and also through a correspondingr spring I2. Beneath the equalizer bar I3 each link 38 carries a clip 39 capable of reacting upward on the equalizer bar.

The levers 35 multiply the force developed by the cylinders 2l, and the parts are so dimensioned that the cylinders 21, when subjected to somewhat less than full braking pressure, set the springs I2 solid. In lieu of setting the springs solid, other means, such as stops distinct from the springs, may be used to limit the approach of the equalizer bar and side frame. Since the springs set up gradually rather than suddenly, it is preferred to close the springs solid and let them serve as the stops. Actually the cylinders 2'I, when active, draw the truck frame downward through the full range of equalizer spring action, and by terminating free spring action prevent the oscillation which heretofore has initiated wheel sliding.

Embodiment of Figs. 4-7

Various equivalent arrangements may be devised, and one is shown in Figs. 4 'to 7, in which parts similar to those shown in Figs. 1 to 3 are given vsimilar reference numerals with the distinguishing letter a.

The truck side frames appear at 9a and cross members at Ila. Two loading cylinders, one at each side of, the truck, are used and onel appears at 21a. The pipe 26a connects with a brake cylinder pipe as in Figs. i -and 2, but the brake cylinders are not illustrated. The levers 35a, two

on each side frame, are pivoted to brackets 36a at their outer ends and when the inner ends of the levers 35a are forced upward, as they are during a brake application, the links 38a (identical in function with the links 38) are drawn upward, since they are pinned at 31a to the levers 35a.

A wedge motion transmitting mechanism is interposed between loading cylinder 21a and the inner ends of a pair of levers 35a. The piston rod Bla is pinned to one end of a lever 4I Whose other end is fulcrumed in bracket 42 carried by side frame 9a. A pair of upstanding guide lugs 43 not only prevent outward displacement of levers 35a but also coniine and guide in horizontal motion transverse to frame 9a a wedge block 44. The block 44 is connected by a link 45 to a point on lever 4| at about mid length thereof so that when cylinder 21a is put under pressure duringa brake application, block 44 is drawn outward, causing the inclined surfaces 46 on the block to react on similarly inclined faces in theinner ends of levers 35a and force the ends of the levers upward, closing the equalizer springs.

The principle of operation is the same as that previously described, but the friction of the wedge surfaces makes the action irreversible, or substantially so, and permits the use of a rather small cylinder. This and the possibility of using two cylinders instead of four somewhat reduces the consumption of air.

Embodiment of Figs. 8 and 9 Both embodiments so far described contemplate closing the equalizersprings, but a similar effect of stabilizing the truck can be had by preventing compression of the 'equalizer springs. To do this some sort of strut member is interposed between the side frame and equalizer bar. In Figs. 8 and 9 two such strut members are set between the side frame and corresponding end portions of the equalizer bar, and exercise a wedging action'upon arcuate seats which the struts engage when active.

This last scheme can be used with oir-thetread brakes such as shown in Figs. 1 to '7. However, because it has special utility with convencylinder 2lb.

l mally oiered by the springs.'

`tional clasp brakes, theseare shown'in Figs. 8 tional manner on the lower portions of the and 9. In these figures parts corresponding to parts in Figs. lv to 3 are given the same reference numerals with the distinguishing letter b.

One of the four wheels is shown at 5b and one ofthe journal boxes at 1b. It is mounted between pedestals 8bv forming a part of the side frame 9b. There are cross members, certain of which appear at Hb, equalizer springs I2b and equalizer bar I3b, all arranged exactly as shown in` Fig. 2 except that' there are rio loading lappearing at 5l.r The usual brake shoe hangers 52 are used. Brake cylinders are not illustrated asit is immaterial how the brake cylinder is arranged. Ordinarily there would be one, lor at most two, truck mounted brake cylinders. 'I'he important point to observe is that,"as in commercial practise, the brake shoe 5| is centered below the center of the wheel Sbwithwhich it c0- acts, so that when the brakes are appliedV the tendency is -to increase the load on the. equalizer springs I2b. As a matter of fact, with ordinary braking pressures the brakes apply a substantial collapsing stress to the equalizing spring wheels. All the embodiments, however, have in common the idea of stabilizing thevtruck, particularly with respect to the equalizer bar, ln such a way as to prevent oscillation and consequent variation of wheel loading. As explained, such variation of wheel loading is the cause, or

at any rate one of the causes, of apparent losses of adhesion `during braking. Stabilization of the truck therefore materially improves the performance of `the brake and permits the attainment erable detail, these embodiments are intended to I2b. Suspended beneath the cross member llb,

is it has tWo pistons 29h between which the actuating air is admitted through the pipe 26h. These pistons are connected to rods 3Ib which Work through guldesin the oppositeends ofthe 'It will be understood that the pipe 2Gb is connected to the brake cylinder pipe so that the pistons will be forced outward whenever the brakes are applied. The rods 3Ib are connected to corresponding ones of a pair of, strut links 53. Each link of the pair is pivoted at 54 to the side frames 9b and so arranged that.

when the piston rods 3lb are forced outward the lower ends of the links 53 coact with the arcuate thrust plates 55 which are carried by the equal-y izer bars |312. Thus, as an incident to an appli-I cation of the brake, the strut links are moved outward to immobilize, or substantially immobilize, the equalizer bars so far as relative movement' with respect to the side frames isconcerned. The parts are so arranged that the vstrut links become eiective before the brake application develops much effect. It follows that the truck is stabilized before the disturbing forces4 lbe'illustrative and not limiting and the scope of the invention is' defined solely in the claims.

What is claimed is: A 1. The combination of a railway car truck having wheels vrwith journalboxes, a frame andv and equalizer springs; iluid pressure brakes including at least one brake cylinder mounted on the truck; and means distinct from the brakes and operable as an incident to a brake application serving to immobilize said frame as to motion relatively to said journal boxes.

2. The combination defined in claim 1 in which the equalizer bars are sustained directly by the journal boxes, the equalizer springs-are interposed between the equalizer bars and said frame, and the immobilizing means serves to fix the equalizer bars relatively to the frame.

3. The combination of a railway car truck having wheels with `-journal boxes, a frame and a spring suspension interposed between the frame and journal boxes,` and including equalizer bars and equalizer springs; iiuid pressure brakes including at least one brake cylinder mounted on the truck; and motor means automatically operable as an incident to a brake application and serving to load said equalizer .springs until they are closed to the limit of their spring action.

4. The combination of a truck comprising wheels with journal boxes, a frame and a spring suspension comprising equalizer bars supported bylsaid journalvboxesl` and equalizer springs interposed between said bars and said frame; fluid pressure brakes including at least one brake cylinder mounted on the truck; and means automatically operableas an incident to a brake apl plication yand then serving to develop a force they set solid, and the other involving'the use of struts which supplant the springs and substitute a rigid support for the yielding support, nor- Tile latter of thereaction between said frame and equalizer bar sufllcient to load .said springs until they are closed to the limit of their spring action.

5. The combination defined in claim 4 in which the means automatically operable as an incident` to a brake application comprise expansiblevchame ber motors connected to be subjected to brake cylinder pressure.

f6. The combination of a railway car truck having wheels with journal boxes, a frame, and a spring suspension interposed between the frame and journal boxes, and including equalizer bars and equalizer springs; -iiuid pressure brakes inl cludingv at least one brake cylinder mounted on the truck; and a plurality of fluid pressurel motors all subject to brake cylinder pressure and each serving when subjected to pressure to suppress motion of a corresponding journal box I relatively to said truck frame.

7 The combination defined in claim 6 in which the motors serve to collapse the equalizer springs to the limit of their spring act-ion.

8. The combination with. the structure dened in claim 6 in which load sustaining means are 

